Its not going to hurt to put the under lug on the barrel , you just don’t want to inlet it tell you know if you have to move the barrel back in the stock or not .
Yes molding = bead work or channel . How it impacts is that I don’t like my pins to be in a thin belly of the stock which is often produced by a nose cap . Thus I put them in the molding so that they have a little more wood around them
I just measured the web between the barrel channel and the RR grove and its 0.26" at the muzzle end, and the barrel tenon is 0.18" so that will give me 0.08" of webbing left.
Maybe , maybe not . At this point you have no real idea as you don’t know if the barrel will still need to be dropped lower , moved back .
This is one of the things that I hate about working with a pre inlet lock mortise . Not only is 99% of the time the lock not in the proper location , But the mortise isn’t inlet so the lock fits . You do realize you will be doing the final fitting on that right ?
Your not expecting the lock to just drop in the hole
that’s why you cant inlet the barrel lugs into the stock yet because some times on pre carves , not only does the barrel have to be brought back to fit the pre carve lock inletting , but it may also have to be inlet deeper down into the stock so that the flash hole ends up center of the side barrel flat OR in the case of using a liner , so that the liner doesn’t end up crossing onto another flat.
Since you pulled the breech plug , did you check to see that the plug was properly faced and mated to the inside shoulder so that it would seal when tightened down ?